Ma nature's got a big crack.
From BBC:
1940: The 8.9-magnitude earthquake which struck Japan on Friday was the strongest in the area in nearly 1,200 years, David Applegate, a senior science adviser at the US Geological Survey, tells the Associated Press. He says the quake ruptured a patch of the earth's crust 240km (150 miles) long and 80km (50 miles) across.
thats the answer! Global sea rise will be off set by global giant earthquakes punching huge holes in the ocean floor!